Pioneer PL-12D Humming/possible grounding issue

amedeofelix

Hi, I have an issue with my Pioneer PL-12D producing a pronounced hum. I have read threads on it, and people experiencing only one channel of hum and issues suggested to be the motor. However, with mine the hum seems to be both channels, it can go away when I fiddle with the ground wire such as remove and replace, and/or touch it to other things like the audio terminals. It goes but then it comes back, and it is there before I turn the platter motor on so cannot be feedback from motor noise. Is it likely the ground wire is simply loose inside the turntable?

Any advice is most welcome.

Mark.Yudkin

The PL-12D's grounding wire needs to be connected to the amplifier's TT ground and the amplifier must be properly earthed. If "fiddling" with that wire helps, your suggestion of a loose wire or dry joint is likely. Open the TT and check.

amedeofelix

I have it connected to the ground on a Phono Preamp, but tried the main amp ground too with same results. OK, I'll have to try opening her up and checking the state of the connections inside. Thanks! I'll come back and update with my findings...

oldcootstereo

Maybe an obvious thing, do you have the pre, amp and TT plugged into the same electrical plug/circuit?  Not uncommon that the wiring in older buildings has been bodged and can be inconsistent in grounding etc. between plugs.

amedeofelix

Ah, yeas with lack of plugs it is likely they are on the same circuit. However, with cleaning the RCA plugs and checking inside to make sure nothing is loose/damaged. I have things to get on with... Couldn't do anything about our electrical circuits if I wanted to sadly - rented flat.